In this project, mechanisms of normal cellular immunity and tumor immunology are studied. Immunological surveillance of cancer patients and the effects of chemotherapy and immunotherapy on the immune response are explored. We are characterizing acute lymphocytic leukemia according to the immunological subtypes of lymphoblasts and the capacity of lymphoblasts to express immunoregulatory helper and/or suppressor functions in vitro. Possible correlation between lymphoblast cell surface markers with various biochemical characteristics is being pursued. Particular emphasis is placed on immunologic study of the monocyte-macrophage system (including development of new clinical assays of human monocyte function) in malignancies and immunodeficiency diseases, in collagen diseases, and in the histiocytoses. We are also investigating serum suppressors of cellular immunity in cancer patients. The therapeutic and diagnostic potential of anti-leukemia antisera and leukemia-specific hybridoma antibodies is being evaluated in vitro and in vivo.